About 225,728 people visited the attraction, which is adjacent to Paine Field and the Boeing factory. That’s up 9 percent from 2011, when 207,000 people paid to visit the Future of Flight.

Barry Smith, executive director for Future of Flight Foundation, attributes the attendance growth to a number factors: a long-term marketing strategy paying off, as well as small things, like directional signs on the interstate.

“We used to have 10 times the number of calls for directions” before the exit sign was installed on I-5, Smith said. That was more than a year ago.

A few years ago, the center’s marketing director, Sandy Ward, also resolved to get the Future of Flight featured in tour operators’ catalogs in Asia and Europe. The aviation attraction has begun to see the fruits of those efforts, Smith said.

Canadians remain the center’s largest group of visitors from outside the United States, Smith said. But China is the fastest-growing set of foreign visitors.

As for U.S. attendance, outside of Washington state, the center draws a lot of visitors from states with a large aerospace presence, like Ohio, Texas, California and Connecticut.

So far this year, attendance is up about 16 percent, Smith said. In previous years, the gains in attendance the Future of Flight saw in January typically held up over the year. The center’s goal is a 9 percent increase in attendance over 2012.

That could be at risk if Boeing engineers go on strike, Smith said. The center, which serves as the base for the Boeing tour, likely would have to shut down the tour during a work stoppage, as it did in 2008 when the Machinists went on strike for 57 days.

More than 1 million people have visited the Future of Flight since the center opened. Future of Flight officials estimate those visitors have generated $139 million in economic impact in the region as visitors stay in local hotels and eat in area restaurants and bars.

Aside from the tourism aspect, the Future of Flight Foundation also hosts several community events, which are paid for with donations and grants. The foundation raised $750,000 last year. Community events include “Family STEM night,” which features activities that highlight science, technology, engineering and math. More than 1,300 people participated in the STEM event Feb. 6.